Many attempts have been made to utilize cellulosic materials, such as alpha-cellulose, as smoking materials to be used as tobacco replacements or supplements. However, alpha-cellulose and similar materials, in untreated form, have not been found to be entirely satisfactory materials, either with regard to their burning characteristics or with regard to certain other properties. Attempts have been made to modify cellulose by oxidative techniques, by heat techniques and by the addition of various materials to modify the properties of the cellulose. Despite these many techniques, cellulose has not been found to be completely satisfactory as a smoking material.
Cellulose has been oxidized by treatment with nitrogen dioxide and similar materials. For example, U.S. Pat. No. 3,461,879 relates to tobacco substitutes in which the combustible portion is oxidized cellulose or is an oxidized material which contains a significant percentage of alpha-cellulose. The theory behind such treatments is believed to involve the oxidation of the primary hydroxyl groups of the cellulose molecule to form carboxyl groups in their place. The oxidation of the cellulose is said to have the effect of reducing the delivery or TPM (total particulate matter) from the cellulose and to also produce a more desirable taste in the smoke. However, such oxidation, for example with nitrogen dioxide, involves relatively high equipment investment and operating costs and does not produce an entirely satisfactory product.
In addition, various heat treatments have been tried, in attempts to improve the burning properties of cellulose. For example, U.S. Pat. Nos. 3,705,589 and 3,545,448 relate to heat-treated cellulosic materials for use in smoking products. However, the materials produced by such treatments have also not been found to be totally satisfactory.
Compositions which have included certain types of untreated cellulose in combination with other materials, for example as described in U.S. Pat. No. 3,807,414, have also not been found to provide all of the desired effects.
It is also well known in the art that smoking articles may be prepared from a variety of combustible or burnable materials and many materials have been suggested for substitutes or as additives for tobacco. However, such compositions have also not been found to be totally satisfactory.
Some of the teachings of the prior art are summarized hereinafter, with patents being presented in numerical order.
U.S. Pat. No. 1,334,752 relates to a fluid for treating tobacco leaves or like plants. The fluid is obtained by boiling resin in a solvent of NaCl and by boiling the same in a solvent of NaHCO.sub.3 and a solution of organic salt of iron.
U.S. Pat. No. 1,680,860 related to a smokeable tobacco substitute and process using eucalyptus, adding glycerine or honey or molasses (as a hydroscopic agent to prevent drying out of the end product). KNO.sub.3 is used in an aqueous solution to treat leaves to augment flagration of the end product so that it is made useable for cigarettes and for pipe smoking purposes. The leaves are air dried, crushed between rollers, macerated in KNO.sub.3 solution for three hours, drained and put in a pressure vessel at 100.degree.-200.degree. F. for three hours. The leaves are then compressed and heated up to 212.degree. F., then shredded as filler.
U.S. Pat. No. 2,576,021 teaches that it is known to use wood pulp to make a paper sheet and soak with tobacco extract to make a tobacco substitute and relates to an improvement using fibers of bagasse preferably sugar cane bagasse preferred over wood pulp, cotton linen, ramie, sisal and other similar fibers because it has a chemical composition similar to tobacco in respect to cellulose, gums, fats and waxes. The process involves washing the sheet and treating it with NaOH or other alkali, and forms a sheet using Fourdrinier equipment. Certain substances can be added to impart desired taste, aroma and color.
U.S. Pat. No. 2,907,686 relates to tobacco substitute, an elongated cylinder made by charring a piece of wood, to produce charcoal. The wood is charred in the absence of air at 250.degree.-800.degree. C. (4-6 hours). The product may include carrier for flavoring agent: charcoal, Fuller's earth, natural or activated clays; aromatic flavoring agent: natural or synthetic oils, e.g. vanilla, eucalyptol, octyl acetate, isoamyl isovalerate. A smoke-forming agent, preferably an edible solid or liquid, e.g. glycerol, glycerol monoacetate, may be added. Coal tar colors may also be added. Ash-forming agent may be from a high ash source or may result from soaking a low ash source with a solution of ash-producing inorganic salts, e.g., ZnCl.sub.2, Ca(OH).sub.2, KOH or K.sub.2 CO.sub.3, MgO, Al.sub.2 O.sub.3. Coating agents, e.g. sugar solutions or hard gum or resin may also be used.
U.S. Pat. No. 3,369,551 relates to a tobacco substitute base found by extracting plant leaves with water or an organic solvent with many additives listed. Dried materials are toasted to a golden brown color and treated with appropriate additives.
U.S. Pat. No. 3,461,879 relates to a tobacco substitute constituting oxidized cellulose in combination with a hydrated metal compound, for example magnesium citrate, hydrated alumina, calcium tartrate or magnesium sulfate. When hydrated metal compounds, for exaple magnesium sulfate or the other materials set forth in this patent are employed, the burning rate of the cellulose has been found to approach that of ordinary cured tobacco leaves and a more pleasant taste and aroma have been found to be produced in connection with the sidestream and mainstream of the tobacco smoke. Furthermore, the resulting ash has been found to be more satisfactory.
U.S. Pat. No. 3,545,448 relates to a smoking material comprising a carbohydrate material, such as cellulose, which is thermally degraded at 100.degree.-250.degree. C. until a weight loss of at least 10% has occurred, the degradation taking place in the presence of a strong mineral acid catalyst or in the presence of a salt of such strong acid with a weak base. The patent indicates that especially useful carbohydrate materials include alpha-cellulose, cellulose derivatives such as methyl cellulose, various polysaccharides and various gums.
U.S. Pat. No. 3,556,109 relates to a smoking material made from oxidized cellulose with various salts.
U.S. Pat. No. 3,556,110 relates to a smoking material made from oxidized cellulose with various salts.
U.S. Pat. No. 3,559,655 relates to a smoking material made from oxidized cellulose with various salts.
U.S. Pat. No. 3,612,063 relates to a smoking material made of oxidized cellulose combined with organic salts of potassium, lithium and copper, such as the oxalic, lactic, glycolic, diglycolic, pivalic or tannic acid salts, and with titanium dioxide.
U.S. Pat. No. 3,638,660 relates to a tobacco substitute material prepared from fibrous wood pulp containing at least 90% of alpha-cellulose which is lightly beaten to certain specifications and is then formed into a sheet having a density of 12-35 pounds per cubic foot. The beaten fibrous wood pulp is, during the formation of the sheet, combined with certain combustion modifiers, namely the sulfates of magnesium, sodium and potassium or the chlorides of potassium and magnesium or the carbonates and bicarbonates of sodium, potassium, magnesium and aluminum or potassium nitrate, ferric oxide, ferric hydroxide, alumina, the citrates and acetates of magnesium and glyconic acid. In the patent, it is stated that best results are obtained when cellulose is combined with hydrated magnesium sulfate and certain burning sustainers, namely potassium chloride, magnesium chloride, potassium sulfate, potassium nitrate and ferric oxide or hydroxide. Other burning sustainers are the potassium, sodium, magnesium and ammonium carbonates or bicarbonates. It is also stated that various flavors and humectants, as well as nicotine or other alkaloids, may be introduced into the sheet. It is further stated that ammonium compounds and various coloring agents may also be incorporated in the sheet. It is also stated that the presence of ammonia (for example in the form of ammonium sulfate or ammonium carbonate) is believed to inhibit the production of 3,4-benzpyrene.
U.S. Pat. No. 3,640,285 relates to a cigarette paper which is loaded with calcium oxalate or certain other alkaline earth metal salts of organic acids, with may be added as such or formed in situ in the paper.
U.S. Pat. No. 3,720,660 relates to oxidized cellulose and other polysaccharides, wherein the cellulose is reacted with such materials as strong acids, e.g. H.sub.2 SO.sub.4, with nitrosyl chloride and the like.
U.S. Pat. No. 3,812,864 relates to a smoking material which is prepared by employing a combination of vinyl methyl ether: maleic anhydride copolymers with certain particulate inorganic materials (for example, calcium carbonates) and with a secondary combustible material which may be tobacco dust, cellulose, pectins, natural gums or the like.
U.S. Pat. No. 3,874,390 relates to a smokable product formed by heating cellulose to 150.degree.-300.degree. C. to obtain a degree of degradation of 5-30% by weight and combining the resulting degraded or carbonized cellulose with an inorganic filler which may be a hydroxide, an oxide or a hydrated oxide of aluminum, iron or silicon, to form a slurry which may then be cast into a sheet for ultimate use as a smoking material.
U.S. Pat. No. 3,924,642 discloses a smokable product having a cellulose based combustible material containing a chelate compound incorporated in an amount from 0.5 to 70% by weight of combustible material. The product may also contain fillers, compounds which split off ammonia, oxidizing agents, ammonium salts of polymeric acids, low sulfur content proteins and/or tobacco extracts.
U.S. Pat. No. 3,931,824 discloses a smoking product which incorporated carboxymethyl cellulose as a portion of its filler.
U.S. Pat. No. 3,965,911 discloses a tobacco substitute smoking material comprising an organic combustible material as a smoke-producing fuel, and protein. The organic combustible material may be a smoke-producing carbohydrate, such as alpha-cellulose, cellulose derivatives, sugars, starch, alginate, pectin, or natural gum.
German Offenlegungsschrift 2,262,829 discloses as a smokable product a cellulose sheet having added thereto a metal chelate of the type represented by magnesium aluminum citrate and magnesium iron citrate.